1. Field of the Invention
The present invention relates to an image forming method and an inkjet recording apparatus, and more particularly, to image formation technology for an inkjet recording apparatus which uses a radiation-curable ink, such as an ultraviolet-curable ink.
2. Description of the Related Art
Inkjet recording apparatuses having an inkjet head in which a plurality of nozzles are arranged, have been known as image forming apparatuses. An inkjet recording apparatus of this kind forms images by forming dots on a recording medium, by ejecting ink as droplets from nozzles, while causing the inkjet head and the recording medium to move relatively to each other.
As inks used in inkjet printers, there are inks which are cured when receiving radiation, such as ultraviolet (UV) light, an electron beam (EB), or the like. An ultraviolet-curable ink (UV ink) is, for example, composed of a coloring material, a polymerizing monomer or oligomer (more specifically, an ultraviolet-curable monomer (UV monomer) or an ultraviolet-curable oligomer (UV oligomer)), and a polymerization initiator and polymerization promoter, and the like, which cause a bridging reaction or polymerization reaction of the monomer or oligomer to take place, due to a photocatalytic reaction. The ink hardens due to the bridging reaction or polymerization reaction when irradiated with ultraviolet light.
In the light-curable ink described in Japanese Patent Application Publication No. 2001-348519, a high-boiling-point wetting agent comprising at least one of a reactive monomer, a reactive oligomer, a reactive polymer, and a reactive sugar, is included in a two-liquid type ink composition, a multivalent metallic salt and photosetting agent are included in an aggregating liquid, and the ink and the aggregating agent are made to react with each other, thereby improving image quality and weather resistance, and preventing “stickiness” of the image section due to residue of the non-volatile wetting agent.
Furthermore, in the ink absorbing body and the image forming apparatus and method using this ink absorbing body described in Japanese Patent Application Publication No. 2001-179959, the coloring material and the solvent component in the ink are separated after deposition of the ink on the recording medium, and only the solvent component is absorbed by the absorbing body having separating properties, thereby promoting drying.
However, in general, when ink of a type that is cured by irradiation of ultraviolet light, or the like, is used (for example, the curable ink described in Japanese Patent Application Publication No. 2001-348519), then relief effects occur in the recording image due to the height of the dots formed on the recording medium.
In the light-curable ink described in Japanese Patent Application Publication No. 2001-348519, it is possible to reduce the height of the dots formed on the recording medium by drying the recording medium after printing, for example, but it is difficult to remove the water content at high speed by means of a small amount of energy. Furthermore, it makes no mention of technology for removing the water content remaining on the recording medium, in order to shorten the drying time, which is a problem in the case of high-speed printing.
Furthermore, in the ink absorbing body and the image forming apparatus and method using the ink absorbing body described in Japanese Patent Application Publication No. 2001-179559, ink coloring material may adhere to the absorbing body, and this ink coloring material adhering to the absorbing body may then become attached to another image or recording medium, thus causing soiling. Furthermore, there is also a problem in that the fixing properties of the ink coloring material are poor in the case of non-permeable recording medium.